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Mbc for Boost Limiter?

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I have a 2005 Subaru Outback XT that's fully built, all I have left to do is a turbo and header upgrade, and it's done power-wise. Im going to get a Tomei unequal length header and a blouch 1.5xtr turbo, I was wondering if I could tune it for peak boost around 25 psi and use a manual boost controller mounted inside the car to reduce max boost on the fly without having to flash a different tune on it. I would want to run 20 psi max for just driving around, but be able to turn it up to 25 psi when I'm racing. The idea makes sense in my head, but the only thing I'm concerned about is that if my EBCS is trying to get the car to reach 25 psi and my MBC is only letting it get to 20 psi idk if that will cause some weird errors and possible boost spike when I turn it up to 25 I don't want it to overboost. Hopefully someone has experience with this setup or can tell me if it flat out won't work. Im using ecu flash and romraider for my tuning software. Thanks

There are numerous ways to do it. You could run spring pressure very close to your 20psi target and run a relay in the power line from a cabin switch to the solenoid so it doesn't cycle, you could mess around with another solenoid to divert the signal and bleed valve but that would probably cost more without much benefit.

By setting spring pressure to around 20psi do you mean the wastegate spring pressure?

I found this product which I'm really in to, just a switch on the inside I can switch between high and low boost.

https://www.turbosmart.com/product/dual-stage-boost-controller-v2-black/

What I cant figure out is where this would be mounted in conjunction with the 3 port ebcs. I would guess that it would go between the ebcs and the wastegate actuator, is this correct?

That would make your other stuff redundant, it's two bleed valves with a solenoid to switch between them.

I was referring to spring combination at your low boost target in the previous response. If you already have the springs, relay, wiring and switch should not be more than $50 even if you buy everything new as single items?